Etching machine



Aug 28, 1951 F. T. POWERS SR ETCHING MACHINE Filed Sept. 50, 1948 4l COMPRESSED A TORNEYS.

gm WWF Patented Aug. 28, 1951 .UNITED STATES PATENT orner 2,566,142 ETGHING MAcnINE FrankT. Powers, Sr., deceased, late of Glen Cove,

tors, ass'ignrs to Powers Photo Engraving ("Joiii-A any: @werden of Nerves Application September 30, 1.9.4.8, .Serial'lQ-ll 1 @Wm (C1.- 17?) The present inventionrelates tol new and use f ul improvements in vapparatus for etching plates in photoengraving, and lfiarticularly for use in connection with relatively Viscous etching fluids.

Objects and advantages of the invention will be set forth in part hereinafter and `in part will be obvious herefrom, or mayfloe learned by practice with the invention, the samev being realized and attained by means of the instrumentalities and combinations pointed out in the appended claim'.

The nventionconsists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

` The accompanying drawings, referred tc herein andconstituting a 'part'hereof,` illustrate one embodiment of the invention, and together with the description, serve te' 'explain the principles ofthe invention. f

Of the drawings:

Figure l is a perspective view with certain parts omitted and with other parts broken away, of an etchinglmachine illustrative of the present invention; V M

Figure 2 is a cross-section of the etching machine shown in Figure 1;"a`nd Figure 3 is' a detailed fragmentary sectional view taken on the line"3-3 of'Figire 2.

The present invention has for its object the provision of an improved etching machine particularly adapted for the economical use of relatively viscous mordants, `such `as ferrie `chloride solution. A further object of the invention is the provision of anetching machinefor etching plates in theprocess of phtoengraving and in which adherent mordant `is removed frein the plate and returned to the bu'lkhof the jrnordant in a reservoir prior to flushingthe surface ofthe plate with water to remove all traces of the mordant from the surface of the plate, thereby preserving the strength of the mordant solution as well as conserving the mordant.

In accordance with the present invention means are provided for subjecting the surface of the plate to be etched to a spray of the etching mordant, and in the case of copper halftone photoengraving, this mordant is usually a relatively concentrated and somewhat viscous solution of ferric chloride. When the etching has been completed, the mordant spray is inter rupted, and in accordance with the present invention the plate is subjected to a strong blast of air which mechanically removes the excess mordant from the surface of the plate and returns it to the etching bath or the reservoir of engraved' plate i mordant, after which the plate is flushed with water to remove any remaining "tracesoffmore dans and also to clean frorntne surface or me plate, any particlesf salts'whieh mayhave dried oruthe surface of the plate.`

In certainrespects the present invent-i013 15.3.11. improvement upon `the etching mahine shown in Powerspnor patent Lsxzaizv @rentar sepj tember 29, 193,1, but tne'ir'i'ventionfmay"be' ap;- plied to 'many other typest'of et'c ing' mach 'es although its greatest usefulness isfprimarily in connection With"the 4etchfg'of foo'pper platesi using `mordants such as n ncentrated solutioi of iron chloride.

It will befunderstood that the foregoing geen eral description`and Vthe/If sc'iption aswell are exe of the invention but y Referring now in" 1 y o y ferre and illustrativeeinbcqimen ofthe iavenf tionfas' 'shown the accompanying drawings, there is provided 'hambfl of generally 'reef-j tangul'arlshp `inthe'bottom of which 1s oontained aduantity offl the etching modalit `ata ancient .eviertofaubw @herstelleibades a e.. die uit@ iras tney'rotat. Blades e are' sup; ported on' a shaft 4 are driven from suitable source o f por r, for i 'tance through pales# 5- astre in Figure 2), a'vigbV vvardl'y, `and `eigoep` operation the spray" baflwll` and a Stati spray is retorna `o' dant 2."

Means are p rovd non' scanne y i into aiidl'utfA f tlie 'Chamb inserted in the chamber for etching, and removed from the chamber for inspection or when the operation has been completed.

Extending horizontally into the chamber l and supported by end walls I3 are horizontal rails I'l and I9 on Which a plate carrier 20 is slidably mounted by means of guide flanges 2| secured to the end Walls 24 and 25 of the plate carrier. The lower edge of the carrier 20 is preferably bent upwardly, as at 23 to provide a trough on which rests the lower edge of the photoengraved plate 25. Trough 23 is provided with suitable openings 26 at its lowermost point so that the etching mordant continually drains therefrom. Surrounding the guide rails IT and I 9, one wall 8 of the chamber l is provided with an opening I8 of sufficient size to admit the plate carrier 20 and the supported plate 25, and this opening is normally closed during the etching operation by the end Wall 24 of the plate carrier, this end wall 24 being slightly larger than the opening IS.

At one side of the etching chamber l, and in a position below the plate carrier 20 when it is slid out of the etching chamber, is a watertight tray 2l adapted to receive any drip from the carrier 2i) or the plate 25, and also to receive the Hushing Water after the plate has been flushed. For ushing the plate after the etching operation has been completed, a pipe 28 is provided with suitable holes through which water is'supplied from pipe 29 under control of a valve 30, these holes directing the spray of water onto the face of the plate 25 when it has been slid from the etching chamber l.

The various parts of the etching machine are made of suitable material resistant to the action of the etching fluid.

Adjacent to the wall 8 of the etching chamber l and within the etching chamber l and extending a distance equal to the vertical height of the plate to be etched is a long, narrow air nozzle 4Q supplied with compressed air from pipe 4| under control of the valve 42. The air blast issuing from the nozzle 40 is obliquely directed against the etched surface of the plate 25 towards the etching chamber, and vigorously blows the retained mordant from the surface of the plate after the etching operation has been completed and as the plate is withdrawn from the etching chamber I preparatory to rinsing the plate Valves 3D and 42 may be in any desired location, but are preferably controlled by separate pedals so that they may be operated without re,

quiring use of the operators hands. The mordant removed from the surface of the plate drains into the bottom of the etching chamber .l Where it joins the main body 2 of the mordant and thus practically no mordant is lost as the plate is removed. Due to the relatively high cost of iron chloride solution, and its viscous nature, its use in many types of etching machines has been commercially unfeasible, but the Vpresent invention avoids this defect.

In the operation of the illustrative embodiment of the invention, the plate to be etched is positioned on the plate carrier 20 with its bottom edge in the trough 23. The paddle-wheel 3 is rapidly rotating and directing a spray upwardly which is normally interrupted by the pivoted baffle Il. After the plate carriage has been slid to the right so as to bring the plate completely into the etching chamber l, the baille Il is lifted to the dot-dash position shown in Figure 2, thereby allowing the spray to be directed against the surface of the plate 25. The etching continues for the desired period of time after which the bale Il is lowered to stop the spray from reaching the plate 25. The operator then opens the compressed air valve 42 and slides the plate carriage 20 to its lefthand position, thereby moving the plate past the air blast issuing from the nozzle 40 and removing the surplus mordant from the face of the plate.

When the plate is positioned over the tray 21, the operator closes valve 42 and opens the valve 30 controlling the flow of flushing Water to the spray pipe 28. This water sprays and flushes the surface of the plate cleaning any trace of the mordant solution or dried salts from the plate, while the flush water drains from the plate into the tray 21, and is thus completely separate from the bulk of the iron chloride solution.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claim without departing from the principles of the inventionr and without sacricing its chief advantages.

What is claimed is:

In an etching machine for photoengraving use having an etching chamber, means for holding a plate to be etched and movable into and out of the chamber, and means for forcing a mordant spray against the face of the plate, the combination with those parts of an air nozzle positioned at the side of the chamber and past which the plate is moved, said air nozzle being supported in a substantially vertical position within the etch-` ing chamber and above the mordant in said chamber, said nozzle having a long narrow slot directed towards the interior of the chamber and transversely across and obliquely to the surface ofthe plate to remove mordant from the surface of the plate and direct the mordant into thev Eecutors of the Estate of Frank T. Powers, Sr.,

Deceased.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,825,127 Powers Sept. 29, 1931 2,293,201 Gaebel Aug. 18, 1942 

